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VITAMINS Vitamins: Any of various organic compounds that are needed in small amounts for normal growth and activity of the body. Most vitamins cannot be synthesized by the body, but are found naturally in foods obtained from plants and animals. Vitamins: are either water - soluble or fat - soluble. Most water - soluble vitamins, such as the vitamin B complex, act as catalysts and coenzymes in metabolic processes and energy transfer and are excreted fairly rapidly. Fat soluble vitamins, such as vitamins A, D, and E are necessary for the function or structural integrity of specific body tissues and membranes and are retained in the body. A- Fat – soluble vitamins: 1- Vitamin D, 2- Vitamin E, 3- Vitamin A, and 4- Vitamin K, B- Water - soluble vitamins: 1- Folate (folic acid), 2- vitamin B12, 3- biotin, vitamin B6, 4- niacin, 5- thiamin, 6- riboflavin, 7- pantothenic acid, and 8- vitamin C (ascorbic acid), 1- Vitamin D (sunshine vitamin) : Vitamin D refers to a group of fat soluble secosteroids responsible for increasing intestinal absorption of calcium, iron, magnesium, phosphate, and zinc. In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol). Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements. Very few foods contain vitamin D; synthesis of vitamin D (specifically cholecalciferol) in the skin is the major natural source of the vitamin. Dermal synthesis of vitamin D from cholesterol is dependent on sun exposure (specifically UVB radiation). UVB: The center of this confusion is the sun's ultraviolet A (long -wave) and ultraviolet B (shortwave) rays. Secosteroids: is a type of steroid with a "broken" ring. The word secosteroid derives from the verb Latin: secare meaning "to cut" and Latin: stere of steroid, meaning "solid, three-dimensional". Secosteroids are alternatively described as a subclass of steroids or derived from steroids. Vitamin D serves several important functions in the body. These include: 1- promoting calcium absorption 2- maintaining normal calcium and phosphate levels 3- promoting bone and cell growth 4- reducing inflammation Vitamin D deficiency doesn’t always cause symptoms. When it does, some of the symptoms may include: 1- Difficulty thinking clearly. 2- Bone pain. 3- Frequent bone fractures. 4- Muscle weakness. 5- Soft bones that may result in deformities. 6- Unexplained fatigue. Vitamin D deficiencies can cause short – term symptoms and long – term complications. Several factors have contributed to the rising incidence of vitamin D deficiency. These include: 1- wearing sunscreen (sun screen blocks the sun’s ability to stimulate vitamin D production). 2- not spending enough time outside. 3- having darkly pigmented skin, which won’t absorb the sun’s rays as well exclusively breast-feeding babies for prolonged time periods. 4- being obese, which typically raises your vitamin D requirements Some people are born without the ability to process vitamin D. Vitamin D deficiency has been shown to play a role in almost every major disease. This includes: 1- Osteoporosis and Osteopenia (reduced bone mass of lesser severity than osteoporosis). 2- Varieties of Cancer (including breast, prostate and colon (. 3- Heart disease. 4- High blood pressure. 5- Obesity. 6- Gout. 7- Depression and Seasonal Affective Disorder. 8- Alzheimer’s Disease. 9- Chronic fatigue syndrome. 10- Fibromyalgia. 2-Vitamin E (Alpha - tocopherol; Gamma - tocopherol) : Vitamin E is a fat-soluble vitamin, which plays a role as an antioxidant in the body. It also helps to prevent free radical damage to specific fats in the body that are critical for our health. Vitamin E: is found in many foods including certain oils, nuts, poultry, eggs, fruits and wheat germ oil. It is also available as a supplement. Function of vitamin E : Vitamin E is an antioxidant. This means it protects body tissue from damage caused by substances called free radicals, which can harm cells, tissues, and organs. -7 2- The body also needs vitamin E to help keep the immune system strong against viruses and bacteria. 3- Vitamin E is also important in the formation of red blood cells and it helps the body use vitamin K. It also helps widen blood vessels and keep blood from clotting inside them. 4- Cells use vitamin E to interact with each other and carry out many important functions. 5- Whether vitamin E benefits include treating and preventing diseases of the heart and blood vessels; such as chest pains, high blood pressure, and blocked or hardened arteries. 6- can prevent cancer, dementia, liver disease, and stroke still requires further research. 7- is an important vitamin that is required for the proper function of many organs in the body. They are believed to play a role in certain conditions related to aging and is extremely useful in naturally slowing aging. Symptoms and Signs of Vitamin E deficiency: The main symptoms of vitamin E deficiency are: 1- Mild hemolytic anemia. 2- Nonspecific neurologic deficits. 3- Vitamin E deficiency may contribute to retinopathy of prematurity (also called retrolental fibroplasia) in premature infants. 4- In adults with malabsorption, vitamin E deficiency very rarely causes spinocerebellar ataxia because adults have large vitamin E stores in adipose tissue. 5- Low levels of vitamin E can cause many digestive system problems, which will lead to poor absorption of nutrients from the digestive tract. This leads to diseases in pancreas, liver, gall bladder etc. Vitamin E Deficiency Diseases: 1- Anaemia: Vitamin E deficiency can cause birth defects of red blood cells . (RBCs) are required for haemoglobin to transport oxygen to other parts of the body., hemolytic anaemia, and degradation of the red blood cells. 2- Poor Balance: Vitamin E deficiency also leads to central nervous system breakdown, poor reflexes, nerve degeneration of the hands, legs, arms and feet, impaired coordination, and loss of balance. 3- Pain, tingling, loss of sensation, gastrointestinal diseases. 4-Dry hair or loss of hair. 5- Slow tissue healing. 6 - Cancer. 7- Atherosclerosis. 9- Blindness. 10- Fertility Problems. 3- Vitamin A: A general term for a group of compounds that includes provitamin A carotenoids (found in foods that come from plants) and retinol (preformed vitamin A found in foods that come from animals). The body can use retinol to make retinal and retinoic acid (other forms of vitamin A). Vitamin A plays an important role in vision, bone growth, reproduction, immunity, cell development, and skin health. Vitamin A is found in some foods, including eggs, liver, milk, cheese, leafy green vegetables (such as spinach, kale, turnip greens, collards, and romaine lettuce), broccoli, dark orange fruits and vegetables (such as apricots, carrots, pumpkin, sweet potatoes, papaya, mango, and cantaloupe), and red bell pepper. Functions of vitamin A Vitamin A plays a role in a variety of functions throughout the body, such as: 1- Vision. 2- Gene transcription. 3- Immune function. 4- Embryonic development and reproduction. 5- Bone metabolism. 6- Haematopoiesis. 7- Skin and cellular health. 8- Antioxidant activity. Vitamin A deficiency: 1- Primary vitamin A deficiency is usually caused by - Prolonged dietary deprivation: - Xerophthalmia due to primary deficiency is a common cause of blindness among young children in developing countries. 1-Secondary vitamin A deficiency may be due to: A- Decreased bioavailability of provitamin A carotenoids B- Interference with absorption, storage, or transport of vitamin A Vitamin A deficiency signs and symptoms: 1- Impaired dark adaptation of the eyes, which can lead to night blindness, is an early symptom of vitamin A deficiency. 2- Xerophthalmia (which is nearly pathognomonic) results from keratinization of the eyes. It involves drying (xerosis) and thickening of the conjunctivae and corneas. 3- Superficial foamy patches composed of epithelial debris and secretions on the exposed bulbar conjunctiva (Bitot spots) develop. 4- In advanced deficiency, the cornea becomes hazy and can develop erosions, which can lead to its destruction (keratomalacia) 5- Keratinization of the skin and of the mucous membranes in the respiratory, GI, and urinary tracts can occur. Drying, scaling, and follicular thickening of the skin and respiratory infections can result. 6- Immunity is generally impaired 7- Growth retardation and infections are common among children. Mortality rate can exceed 50% in children with severe vitamin A deficiency. 4- Vitamin K: Functions of vitamin K: 1- Preventing bleeding problems in newborns with low levels of vitamin K (hemorrhagic disease). 2- Treating and preventing bleeding problems in people with low levels of the blood clotting protein prothrombin. 3- An inherited bleeding disorder called vitamin K-dependent clotting factors deficiency (VKCFD). Taking vitamin K by mouth or injecting it intravenously helps prevent bleeding in individuals with VKCFD. 4- Reversing the effects of too much warfarin used to prevent blood clotting. Taking vitamin K1 by mouth or as in injection into the vein can counteract too much anticoagulation caused by warfarin. 5- Taking vitamin K along with warfarin also seems to help stabilize blood clotting time in people taking warfarin, especially those who have low vitamin K levels. Signs and Symptoms of vitamin K deficiency: The signs and symptoms associated with vitamin K deficiency may include: 1- Easy bruising. 2- Oozing from nose or gums. 3- Excessive bleeding from wounds, punctures, and injection or surgical sites. 4- Heavy menstrual periods. 5- Bleeding from the gastrointestinal (GI) tract. 6- Blood in the urine and/or stool. 7- Increased prothrombin time (PT). Causes of Vitamin K Deficiency The most common causes of vitamin K deficiency are: 1- insufficient dietary intake, 2- inadequate absorption, 3-decreased storage of the vitamin due to liver disease, 4-it may also be caused by decreased production in the intestine 5- it is often seen in cancer patients on chemotherapy, chronic dialysis patients, and patients who are at risk for malnutrition, such as those with a poor diet associated with alcohol or drug abuse. 6- Malabsorption, especially impaired absorption of fats due to diseases such as cystic fibrosis, celiac disease, chronic pancreatitis or Crohns disease, may cause vitamin K deficiency. 7- Choleostatic liver diseases such as a bile duct obstruction or primary biliary cirrhosis can also lead to malabsorption and a deficiency in vitamin K. Water soluble vitamins: Water - soluble vitamins travel freely through the body, and excess amounts usually are excreted by the kidneys. The body needs water-soluble vitamins in frequent, small doses. These vitamins are not as likely as fat-soluble vitamins to reach toxic levels. But niacin, vitamin B6, folate, choline, and vitamin C have upper consumption limits. Vitamin B6 at high levels over a long period of time has been shown to cause irreversible nerve damage. Water-soluble vitamins B- complex Energy – releasing vitamins: 1- Thiamine (vit B1) 2- Riboflavin ( vit. B2) 3- Niacin (vit B3) 4- Biotin. 5- Pantothenic acid. Haematopoitic vitamins: 1.Folic acid. 2.Vit. B12 Other vitamins 1.Pyridoxine (vit B6) 2.Pyridoxal. 3.Pyridoxamine. Thiamine (vitamine B1) The active form of vit B1 is diphosphate, which is converted by ATP – dependant enzyme present in the brain and liver called diphospho transferase. Thiamine pyrophosphotase is a coenzyme serves in enzymatic reactions: 1.Transketolase reaction; that is necessary for the formation of glyceraldehydes 3-p 2.It is also involved in citric acid cycle. Deficiency of thiamine: 1- Periphral neuropathy and anorexia, odema, cardiovascular and muscular degeneration. 2- Beri-Beri disease is a severe deficiency of thiamine. RIBOFLAVIN (Vitamine B2 ) The active forms of riboflavin are: 1.Flavin mononucleotide (FMN) 2.Flavin adenine dinucleotide (FAD). FMN is formed by ATP-dependant phosphorylation of riboflavin; while FAD is synthesized by a further reaction with ATP in which the AMP moiety of ATP is transferred to FMN. Its function as coenzymes; Deficiency of Riboflavin: Include: 1. Dermatitis. 2. Cheilosis. (Fissuring at the corners of the mouth). 3. Glossitis( the tongue appears smooth and purplish). Niacin (Nicotinic acid and Nicotinamide) : Are both coenzymes for many oxido-reductase . They act with enzymes dehydrogenase; involved in carbohydrate,lipids and aminoacids metabolismas in the citric acid cycle. Distibution : It is found in most animal and plant food Clinical indication for Niacin; A .Deficiency of Niacin leads weight loss, dermatitis, digestive disorders. ,diarrhea.and depression(central nervous system). B. Treatment of hyperlipidemia Nicotinic acid is used for lowering serum cholesterol, due to inhibition of free fatty acid from adipose tissue. Biotin It is a coenzyme in carboxylation reactions in which it serves as a carrier of activated carbon dioxide Deficiency of Biotin Biotin deficiency does not occur naturally because the vitamin is widely distributed in food. PANTOTHENIC ACID The active form of it is the [ coenzyme A] . CoA occurs in citric acid cycle. Fatty acid synthesis, oxidation and acylation reaction and cholesterol synthesis. Its functions in the transfer of acyl groups. Pyridoxine( vitamine B6) Vitamin B6 consist of 3 closely related naturally occurring pyridine derivatives. 1.Pyridoxine 2.Pyridoxal. 3.Pyridoxamine. All these three derivatives are equal in activity as precursors for the coenzyme ,this coenzyme helps many enzyme of amino acid metabolism. The reactions are transamination, Deamination, Decarboxylation and condensation. FOLIC ACID Folacin has the biochememical activity of folic acid. Yeast, liver , leafy vegetables are the major sources for folic acid. Active folate: is the tetrahydrofolate which is formed by a reduction occurs in the intestinal cells by the enzyme folate reductase,in this reaction NADPH is used as a donor for [H]. Clinical indication: Folic acid deficiency result in growth failure and megaloblastic anemia (decrease DNA synthesis): this state may be caused by: 1. Increased demand with adequate loss of folate such as in pregnancy and lactation. 2. Poor absorption due to pathological disorder of the small intestine. 3. Alcoholism. Vitamin B12 (cobalamine) It is synthesized by microorganisms , liver is also a good source for vitamin B12 ,the commercial preparation is cyanocobalamin. The active coenzyme forms of Vit B12 are : 1- Methylcobalamine. 2- Deoxyadenosylcobalamine which help in the conversion of methylmalanoyl-CoA to succinyl CoA (in the citric acid cycle). Absorption of Cobalamine: Mammals absorbed cobalamine using aspecialized transport system.,here the stomach secret a glycoprotein called INTRINSIC FACTOR (IF),which binds cobalamine to the intestinal lumen. Nutritional deficiency of cobalamine is rare except in strict vegetarian;as this vitamin is found in all animal sources. Methylcobalamine is coenzyme in the combined conversion of : 1. Homocysteine to methanionine and 2. Methyltetrahydrofolate to tetrahydrofolate Ascorbic acid (vitamin C): Vit C act as coenzyme Acts as a donor of reducing equivalents and it is oxidized Dehydroascorbic acid, which is a source of vitamin C. Clinical Indication of Vit C: 1-Deficiency of Vit C results in scurvy 2. Prevention of chronic diseases: Vitamin C act as antioxidants (i.e inactivate the free radicals). Water soluble vitamins Water soluble vitamins Thiamine (vitamin B1) Function Part of an enzyme needed for energy metabolism; important to nerve function. Riboflavin (vitamin B2) Part of an enzyme needed for energy metabolism; important for normal vision and skin health. Niacin (vitamin B3) Part of an enzyme needed for energy metabolism; important for nervous system, digestive system, and skin health. Pantothenic acid Part of an enzyme needed for energy metabolism. Biotin Part of an enzyme needed for energy metabolism. Pyridoxine (vitamin B6) Part of an enzyme needed for protein metabolism; helps make red blood cells. Folic acid Part of an enzyme needed for making DNA and new cells, especially red blood cells. Cobalamin (vitamin B12) Part of an enzyme needed for making new cells; important to nerve function. Ascorbic acid (vitamin C) Antioxidant; part of an enzyme needed for protein metabolism; important for immune system health; aids in iron absorption. Water soluble vitamins deficiency disease Water soluble vitamins Thiamine (vitamin B1) Disease Rare- Beriberiloss of muscle function, nerve damage, mental confusion. Riboflavin (vitamin B2) Uncommonanemia mouth sores, sore throat, swelled mucous membranes, and skin disorders. Niacin (vitamin B3) Pellagra is characterized by the 4 D’s Dermatitis, Diarrhea, Dementia, and Death Pantothenic acid Very rare- only seen in severe malnutrition Symptoms are headache, fatigue, burning and numbness of feet. Biotin Rare but symptoms include hair loss dry scaly skin, cheilitis, fatigue and depression. Pyridoxine (vitamin B6) ,uncommon but includes convulsions, nausea depression, anemia, and dermatitis. Folic acid anemia, birth defects, and slowed growth during growing phase. It is very important for women of childbearing age to get enough folic acid even if not expecting to be pregnant. Cobalamin (vitamin B12) Pernicious anemiarare, symptoms are anemia, ,fatigue, weight loss, neurological damage and cognitive impairment. Ascorbic acid (vitamin C) ,Scurvy, symptoms are bleeding bruising easily, hair and teeth loss, joint pain and swelling and in severe cases death.